The article transport facility described above is installed in e.g. a cleanroom for transporting a storage container storing therein a substrate such as a silicone substrate as an article.
More particularly, the traveling rail is disposed through/across carry in/out sections of a plurality of substrate processing devices for carrying out a plurality of kinds of processing on a substrate and the article transport carriage transports the article to/from the plurality of substrate processing devices. And, the article loading unit is used for temporarily storing the article in the course of its processing.
Namely, as the article loading unit, a plurality of them can be provided respectively at a plurality of positions of the traveling rail along the length thereof through utilization of space available laterally of the traveling rail. Thus, the arrangement of temporarily storing a mid-processing article, that is, an article in the middle of its processing, in an article loading unit present nearby a substrate processing device to which this article is to be transported next, will be advantageous for improvement of article transporting efficiency. Further, in case no such article loading unit (units) is (are) provided, if a storage unit for storing mid-processing articles is to be provided on a floor surface, this storage unit needs to be large. On the other hand, with provision of the article loading units, omission or down-sizing of such storage unit becomes possible.
Further, in an article transport facility, when the substrate processing devices are to be carried in/out of e.g. a cleanroom for change of layout thereof, the presence of the article loading units can be obstructing, e.g. an article loading unit disposed on the side of the ceiling portion but downwardly of the traveling rail obstructing the transporting of the substrate processing devices. In such case, since the article loading unit can be changed in its position from the transferring position to the retracted position retracted upwards from the transferring position, the obstruction by the article loading unit can be avoided.
Japanese Unexamined Patent Application Publication No. 2008-169005 (Patent Document 1) discloses an example of such article transport facility as described above. The article loading unit provided in this article transport facility is supported to be position-changeable under its no-article loading state, between a transferring position and a retracted position.
Namely, in this Patent Document 1, the article loading unit is hung and supported by a ceiling portion via a link mechanism comprised of a plurality of links connected to be flexible to each other. When the article loading unit is to be positioned at the transferring position, the link mechanism is caused to assume a linearly extended posture. Whereas, when the article loading unit is to be positioned at the retracted position, the link mechanism is caused to assume a flexed posture overlapping the article loading unit from above. Therefore, when the article loading unit is changed in its position from the transferring position to the retracted position, no space for allowing presence of the article is secured upwardly of the article loading unit. As a result, no article can be loaded on the article loading unit when this unit is positioned at the retracted position.
Moreover, in the article transport facility disclosed in Patent Document 1, when the article loading unit is positioned at the retracted position, the spacing between this article loading unit and the ceiling portion becomes smaller than the spacing required for allowing presence of article. In this respect too, when the article loading unit is changed in its position from the transferring position to the retracted position, no space for allowing presence of the article is secured upwardly. As a result, no article can be loaded on the article loading unit when this unit is positioned at the retracted position.
Incidentally, in Patent Document 1, there is described as a further embodiment using a slide mechanism vertically slidable for position-changing the article loading unit between the transferring position and the retracted position. However, even with use of such slide mechanism, when the article loading unit is positioned at the retracted position, the spacing between this article loading unit and the ceiling portion becomes smaller than the spacing required for allowing presence of article. Thus, no article can be loaded on the article loading unit when this unit is positioned at the retracted position.
When there arises a need to retract an article loading unit from the transferring position to the retracted position, it may be that this article loading unit is currently loading an article thereon. In such case, in the case of the conventional article transport facility, it is necessary to first remove manually the article from the article loading unit and then to change the position of the article loading unit to the retracted position. Therefore, the operation for position-changing the article loading unit between the transferring position and the retracted position is troublesome.
Furthermore, after the article loading unit has been returned from the retracted position to the transferring position, it is necessary to manually return the once-removed article back to the same previous state. Hence, in this respect too, the operation for position-changing the article loading unit between the transferring position and the retracted position is troublesome.
Meanwhile, the positions of articles to be transported are managed by a managing means for managing the article transport facility. Therefore, when a once-removed article is manually retuned to the article loading unit, it is necessary to return it accurately to the same position as the position thereof prior to the removal.
However, in such a situation when a plurality of article loading units are simultaneously retracted to the retracted positions, there can occur an error that the position to which the removed article is to be returned differs from the previous one, so that appropriate position management of the transported articles becomes impossible.